1. Field of the Invention
This invention relates to an image sensing method and an apparatus therefor. More particularly, the invention relates to an image sensing method and apparatus in which digital signal processing is executed.
2. Description of the Related Art
A color image sensing method available in the prior art performs color image sensing using a single solid-state image sensing element composed of very small color filters arrayed on an image sensing surface. According to this method, carrier components of a color signal are removed from the output of the image sensing element to form an intensity signal, a color signal is formed by synchronously detecting the carrier components, and the color and intensity signals are processed separately to synthesize a color image signal.
Many image recording/playback apparatus have been proposed for recording the image signal on video tape and playing back the image signal. 25 In particular, many systems, in which a high-speed analog/digital converter (hereinafter referred to as an "AD converter") and a digital/analog converter (hereinafter referred to as a "DA converter") is used, have recently been proposed. These systems are arranged to convert the image signal into a digital signal using the AD converter, execute digital signal processing such as filtering, gamma-correction, a matrix operation and clipping necessary in the image sensing apparatus, effect a digital-to-analog conversion, store the results on tape and playback and output the image when necessary.
Further, systems have been proposed in which special effects such as freezing of the picture and intermittent image sensing are obtained using a field memory.
However, in these prior-art image sensing apparatus using digital signal processing, the circuitry is large in which use is made of a high-speed analog/digital converter (hereinafter referred to as an "AD converter") and a digital/analog converter (hereinafter referred to as a "DA converter") scale, the number of component parts is large, a large amount of current is consumed, the apparatus cannot be reduced in size and cost cannot be reduced.